Kids' food allergies may be rarer than parents think, says study

By Stephen Daniells

- Last updated on GMT

Related tags: Allergy

Parents may be overestimating the occurrence of food allergies by
as much as two times, putting their child at risk of inadequate
nutrition, say researchers from the UK.

"[There is a] need for accurate diagnosis to prevent infants being on unnecessarily restricted diets, which may be associated with inadequate nutrition in this important period of growth and development,"​ wrote the researchers from the University of Portsmouth.

Growing consumer concern and public awareness of food allergies and intolerance is boosting the free-from food market, and has enjoyed sales growth of over 300 per cent in the UK since 2000, according to market analyst Mintel.

An estimated four per cent of adults and eight per cent of children in the 380m EU population suffer from food allergies, according to the European Federation of Allergy and Airways Diseases Patients' Associations.

But diagnosis by parents may be overestimating the problem, says the new research published in the Journal of Allergy and Clinical Immunology​ (Vol. 117, pp. 1118-1124).

The researchers, led by Dr. Taraneh Dean, recruited 969 pregnant women between September 2001 and August 2002. Parental reporting of food hypersensitivity was recorded every three months during the first year of the child's life by means of a standardised questionnaire. By the end of the year-long study, 92.9 per cent of the participants (900) were still responding.

Food hypersensitivity was reported by 132 parents after three months (cow's milk), 83 parents after six months (cow's milk, non-citrus fruit, baby rice, oats), 49 parents after nine months (cow's milk, egg and tomato), and 65 parents after one year (cow's milk, egg, tomato and fish).

In all, cumulative perceived adverse reactions to food were reported for 25.8 per cent of the children by one year of age.

The researchers then assessed the prevalence of food hypersensitivity between six and nine months, and nine and twelve months by means of food challenges. The open food challenges (OFCs) demonstrated food hypersensitivity in 14 per cent of the children, while double-blind, placebo-controlled food challenges (DBPCFC), the so-called gold standard for establishing food hypersensitivity, confirmed only six per cent.

A study performed in 1987 reported that about one quarter of kids with apparent food allergies actually had evidence of the allergy (Pediatrics​, Vol. 79, pp. 683-688). In this new study, the number is actually half that again, say the researchers.

"We have established that a quarter of parents report adverse reactions to food in their infants during the first year of life. Of these, only an eighth were confirmed as food hypersensitive by open food challenges,"​ concluded the researchers.

There are two main limitations with this study. Firstly, the DBPCFC was not taken by every child but by only 60 per cent. This however is consistent with other infant food allergy studies, say the scientists. Secondly, no allergy tests were performed for peanuts or sesame since it was decided not to exposure the one-year infants to these potential allergens this, admit the authors, could have underestimated the actual rate of food hypersensitivity.

The study coincides with another study published by American researchers in the journal Pediatrics​ (Vol. 117, pp. 2175-2182), which reports that earlier exposure of infants to solid foods, specifically in the case of wheat, could reduce the chance of developing wheat allergy.

Muriel Simmons, chief executive of Allergy UK told that the results are not so unexpected since mothers are naturally cautious with the health of their child, but that limited numbers of allergy specialists meant that confirmation of a perceived allergy is not always possible.

"Mothers with infants who are displaying symptoms that cause distress obviously want to identify the trigger to the symptoms so that they can deal with the problem. However mothers generally find it very difficult to get a referral to an appropriately qualified allergy specialist as we simply do not have sufficient numbers of specialists available.

An important part of the role of a good allergy specialist is to actually identify whether the symptoms are due to allergy or not. A diagnosis that a baby is not showing symptoms of allergic disease is just as important as a diagnosis showing that it is allergic disease causing the problem,"​ she said.

Allergen labelling regulations that came into force on 25 November require companies to label all pre-packed foods if they contain any of the 12 listed allergenic foods as an ingredient.

The mandatory inclusion on food labels of the most common food allergen ingredients and their derivatives covers cereals containing gluten, fish, crustaceans, egg, peanut, soybeans, milk and dairy products including lactose, nuts, celery, mustard, sesame seed, and sulphites.

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